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From: "Stefan Mätje" <Stefan.Maetje@esd.eu>
To: linux-can@vger.kernel.org, Marc Kleine-Budde <mkl@pengutronix.de>,
	Wolfgang Grandegger <wg@grandegger.com>
Cc: netdev@vger.kernel.org, "Stefan Mätje" <Stefan.Maetje@esd.eu>
Subject: [PATCH v2 1/1] can: esd: add support for esd GmbH PCIe/402 CAN interface family
Date: Fri, 30 Jul 2021 19:38:05 +0200	[thread overview]
Message-ID: <20210730173805.3926-2-Stefan.Maetje@esd.eu> (raw)
In-Reply-To: <20210730173805.3926-1-Stefan.Maetje@esd.eu>

This patch adds support for the PCI based PCIe/402 CAN interface family
from esd GmbH that is available with various form factors
(https://esd.eu/en/products/402-series-can-interfaces).

All boards utilize a FPGA based CAN controller solution developed
by esd (esdACC). For more information on the esdACC see
https://esd.eu/en/products/esdacc.

This driver detects all available CAN interface boards but atm.
operates the CAN-FD capable devices in Classic-CAN mode only!
A later patch will introduce the CAN-FD functionality in this
driver.

Signed-off-by: Stefan Mätje <Stefan.Maetje@esd.eu>
---
 drivers/net/can/Kconfig                |   1 +
 drivers/net/can/Makefile               |   1 +
 drivers/net/can/esd/Kconfig            |  12 +
 drivers/net/can/esd/Makefile           |   7 +
 drivers/net/can/esd/esd_402_pci-core.c | 530 ++++++++++++++++++
 drivers/net/can/esd/esdacc.c           | 717 +++++++++++++++++++++++++
 drivers/net/can/esd/esdacc.h           | 394 ++++++++++++++
 7 files changed, 1662 insertions(+)
 create mode 100644 drivers/net/can/esd/Kconfig
 create mode 100644 drivers/net/can/esd/Makefile
 create mode 100644 drivers/net/can/esd/esd_402_pci-core.c
 create mode 100644 drivers/net/can/esd/esdacc.c
 create mode 100644 drivers/net/can/esd/esdacc.h

diff --git a/drivers/net/can/Kconfig b/drivers/net/can/Kconfig
index fff259247d52..47cfb6ae0772 100644
--- a/drivers/net/can/Kconfig
+++ b/drivers/net/can/Kconfig
@@ -170,6 +170,7 @@ config PCH_CAN
 
 source "drivers/net/can/c_can/Kconfig"
 source "drivers/net/can/cc770/Kconfig"
+source "drivers/net/can/esd/Kconfig"
 source "drivers/net/can/ifi_canfd/Kconfig"
 source "drivers/net/can/m_can/Kconfig"
 source "drivers/net/can/mscan/Kconfig"
diff --git a/drivers/net/can/Makefile b/drivers/net/can/Makefile
index a2b4463d8480..5d5aeaaf02d7 100644
--- a/drivers/net/can/Makefile
+++ b/drivers/net/can/Makefile
@@ -12,6 +12,7 @@ obj-y				+= rcar/
 obj-y				+= spi/
 obj-y				+= usb/
 obj-y				+= softing/
+obj-y				+= esd/
 
 obj-$(CONFIG_CAN_AT91)		+= at91_can.o
 obj-$(CONFIG_CAN_CC770)		+= cc770/
diff --git a/drivers/net/can/esd/Kconfig b/drivers/net/can/esd/Kconfig
new file mode 100644
index 000000000000..54bfc366634c
--- /dev/null
+++ b/drivers/net/can/esd/Kconfig
@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0-only
+config CAN_ESD_402_PCI
+	tristate "esd electronics gmbh CAN-PCI(e)/402 family"
+	depends on PCI && HAS_DMA
+	help
+	  Support for C402 card family from esd electronics gmbh.
+	  This card family is based on the ESDACC CAN controller and
+	  available in several form factors:  PCI, PCIe, PCIe Mini,
+	  M.2 PCIe, CPCIserial, PMC, XMC  (see https://esd.eu/en)
+
+	  This driver can also be built as a module. In this case the
+	  module will be called esd_402_pci.
diff --git a/drivers/net/can/esd/Makefile b/drivers/net/can/esd/Makefile
new file mode 100644
index 000000000000..5dd2d470c286
--- /dev/null
+++ b/drivers/net/can/esd/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+#  Makefile for esd gmbh ESDACC controller driver
+#
+esd_402_pci-objs := esdacc.o esd_402_pci-core.o
+
+obj-$(CONFIG_CAN_ESD_402_PCI) += esd_402_pci.o
diff --git a/drivers/net/can/esd/esd_402_pci-core.c b/drivers/net/can/esd/esd_402_pci-core.c
new file mode 100644
index 000000000000..191e7f45c5d9
--- /dev/null
+++ b/drivers/net/can/esd/esd_402_pci-core.c
@@ -0,0 +1,530 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2015 - 2017 esd electronic system design gmbh
+ * Copyright (C) 2017 - 2021 esd electronics gmbh
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/pci.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include <linux/netdevice.h>
+#include <linux/dma-mapping.h>
+#include <linux/can.h>
+#include <linux/can/dev.h>
+#include <linux/can/netlink.h>
+
+#include "esdacc.h"
+
+#define DRV_NAME			"esd_402_pci"
+
+#define ESD_PCI_DEVICE_ID_PCIE402	0x0402
+
+#define PCI402_FPGA_VER_MIN		0x003d
+#define PCI402_MAX_CORES		4
+#define PCI402_BAR			0
+#define PCI402_IO_OV_OFFS		0
+#define PCI402_IO_PCIEP_OFFS		0x10000
+#define PCI402_IO_LEN_TOTAL		0x20000
+#define PCI402_IO_LEN_CORE		0x2000
+#define PCI402_PCICFG_MSICAP_CSR	0x52
+#define PCI402_PCICFG_MSICAP_ADDR	0x54
+#define PCI402_PCICFG_MSICAP_DATA	0x5c
+
+#define PCI402_DMA_MASK			(DMA_BIT_MASK(32) & 0xffff0000)
+#define PCI402_DMA_SIZE			ALIGN(0x10000, PAGE_SIZE)
+
+#define PCI402_PCIEP_OF_INT_ENABLE	0x0050
+#define PCI402_PCIEP_OF_BM_ADDR_LO	0x1000
+#define PCI402_PCIEP_OF_BM_ADDR_HI	0x1004
+#define PCI402_PCIEP_OF_MSI_ADDR_LO	0x1008
+#define PCI402_PCIEP_OF_MSI_ADDR_HI	0x100c
+
+/* The BTR register capabilities described by the can_bittiming_const structures
+ * below are valid since ESDACC version 0x0032.
+ */
+
+/* Used if the ESDACC FPGA is built as CAN-Classic version. */
+static const struct can_bittiming_const pci402_bittiming_const = {
+	.name = "esd_402",
+	.tseg1_min = 1,
+	.tseg1_max = 16,
+	.tseg2_min = 1,
+	.tseg2_max = 8,
+	.sjw_max = 4,
+	.brp_min = 1,
+	.brp_max = 512,
+	.brp_inc = 1,
+};
+
+/* Used if the ESDACC FPGA is built as CAN-FD version. */
+static const struct can_bittiming_const pci402_bittiming_const_canfd = {
+	.name = "esd_402fd",
+	.tseg1_min = 1,
+	.tseg1_max = 256,
+	.tseg2_min = 1,
+	.tseg2_max = 128,
+	.sjw_max = 128,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+
+#if ACC_ENABLE_CANFD
+static const struct can_bittiming_const pci402_bittiming_const_canfd_data = {
+	.name = "esd_402fd",
+	.tseg1_min = 1,
+	.tseg1_max = 32,
+	.tseg2_min = 1,
+	.tseg2_max = 16,
+	.sjw_max = 16,
+	.brp_min = 1,
+	.brp_max = 256,
+	.brp_inc = 1,
+};
+#endif
+
+static const struct net_device_ops pci402_acc_netdev_ops = {
+	.ndo_open = acc_open,
+	.ndo_stop = acc_close,
+	.ndo_start_xmit = acc_start_xmit,
+	.ndo_change_mtu = can_change_mtu
+};
+
+struct pci402_card {
+	/* Actually mapped io space, all other iomem derived from this */
+	void __iomem *addr;
+	void __iomem *addr_pciep;
+
+	void *dma_buf;
+	dma_addr_t dma_hnd;
+
+	struct acc_ov ov;
+	struct acc_core cores[PCI402_MAX_CORES];
+
+	bool msi_enabled;
+	int irq_stack;
+};
+
+static irqreturn_t pci402_interrupt(int irq, void *dev_id)
+{
+	struct pci_dev *pdev = dev_id;
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	irqreturn_t irq_status;
+	int irq_level_out;
+	int irq_level_in;
+
+	/* Use <irq_stack> to check for IRQ multi service on multiple CPUs. */
+	irq_level_in = __sync_fetch_and_add(&card->irq_stack, 1);
+
+	irq_status = acc_card_interrupt(&card->ov, card->cores);
+
+	irq_level_out = __sync_sub_and_fetch(&card->irq_stack, 1);
+
+	if (irq_level_in || irq_level_out) {
+		pci_warn(pdev, "%s(): Bad level, in %d, out %d\n",
+			 __func__, irq_level_in, irq_level_out);
+	}
+
+	return irq_status;
+}
+
+static int pci402_set_msiconfig(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	u32 addr_lo_offs = 0;
+	u32 addr_lo = 0;
+	u32 addr_hi = 0;
+	u32 data = 0;
+	u16 csr = 0;
+	int err;
+
+	err = pci_read_config_word(pdev, PCI402_PCICFG_MSICAP_CSR, &csr);
+	if (err)
+		goto failed;
+
+	err = pci_read_config_dword(pdev, PCI402_PCICFG_MSICAP_ADDR, &addr_lo);
+	if (err)
+		goto failed;
+	err = pci_read_config_dword(pdev, PCI402_PCICFG_MSICAP_ADDR + 4,
+				    &addr_hi);
+	if (err)
+		goto failed;
+
+	err = pci_read_config_dword(pdev, PCI402_PCICFG_MSICAP_DATA, &data);
+	if (err)
+		goto failed;
+
+	addr_lo_offs = addr_lo & 0x0000ffff;
+	addr_lo &= 0xffff0000;
+
+	if (addr_hi)
+		addr_lo |= 1; /* Enable 64-Bit addressing in address space */
+
+	if (!(csr & 0x0001)) { /* Enable bit */
+		err = -EINVAL;
+		goto failed;
+	}
+
+	iowrite32(addr_lo, card->addr_pciep + PCI402_PCIEP_OF_MSI_ADDR_LO);
+	iowrite32(addr_hi, card->addr_pciep + PCI402_PCIEP_OF_MSI_ADDR_HI);
+	acc_ov_write32(&card->ov, ACC_OV_OF_MSI_ADDRESSOFFSET, addr_lo_offs);
+	acc_ov_write32(&card->ov, ACC_OV_OF_MSI_DATA, data);
+
+	return 0;
+
+failed:
+	pci_warn(pdev, "Error while setting MSI configuration:\n"
+		 "CSR: 0x%.4x, addr: 0x%.8x%.8x, data: 0x%.8x\n",
+		 csr, addr_hi, addr_lo, data);
+
+	return err;
+}
+
+static int pci402_init_card(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+
+	card->ov.addr = card->addr + PCI402_IO_OV_OFFS;
+	card->addr_pciep = card->addr + PCI402_IO_PCIEP_OFFS;
+
+	acc_reset_fpga(&card->ov);
+	acc_init_ov(&card->ov, &pdev->dev);
+
+	if (card->ov.version < PCI402_FPGA_VER_MIN) {
+		pci_err(pdev,
+			"ESDACC version (0x%.4x) outdated, please update\n",
+			card->ov.version);
+		return -EINVAL;
+	}
+
+	if (card->ov.active_cores > PCI402_MAX_CORES) {
+		pci_warn(pdev,
+			 "Card has more active cores than supported by driver, %u core(s) will be ignored\n",
+			 card->ov.active_cores - PCI402_MAX_CORES);
+		card->ov.active_cores = PCI402_MAX_CORES;
+	}
+
+	if (card->ov.features & ACC_OV_REG_FEAT_MASK_CANFD) {
+		pci_warn(pdev,
+			 "ESDACC with CAN-FD feature detected. This driver doesn't support CAN-FD yet.\n");
+	}
+
+#ifdef __LITTLE_ENDIAN
+	/* So card converts all busmastered data to LE for us: */
+	acc_ov_set_bits(&card->ov, ACC_OV_OF_MODE,
+			ACC_OV_REG_MODE_MASK_ENDIAN_LITTLE);
+#endif
+
+	return 0;
+}
+
+static int pci402_init_interrupt(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	int err;
+
+	err = pci_enable_msi(pdev);
+	if (!err) {
+		err = pci402_set_msiconfig(pdev);
+		if (!err) {
+			card->msi_enabled = true;
+			acc_ov_set_bits(&card->ov, ACC_OV_OF_MODE,
+					ACC_OV_REG_MODE_MASK_MSI_ENABLE);
+			pci_info(pdev, "MSI enabled\n");
+		}
+	}
+
+	err = devm_request_irq(&pdev->dev, pdev->irq, pci402_interrupt,
+			       IRQF_SHARED, dev_name(&pdev->dev), pdev);
+	if (err)
+		goto failure_msidis;
+
+	iowrite32(1, card->addr_pciep + PCI402_PCIEP_OF_INT_ENABLE);
+
+	return 0;
+
+failure_msidis:
+	if (card->msi_enabled) {
+		acc_ov_clear_bits(&card->ov, ACC_OV_OF_MODE,
+				  ACC_OV_REG_MODE_MASK_MSI_ENABLE);
+		pci_disable_msi(pdev);
+		card->msi_enabled = false;
+	}
+
+	return err;
+}
+
+static void pci402_finish_interrupt(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+
+	iowrite32(0, card->addr_pciep + PCI402_PCIEP_OF_INT_ENABLE);
+	devm_free_irq(&pdev->dev, pdev->irq, pdev);
+
+	if (card->msi_enabled) {
+		acc_ov_clear_bits(&card->ov, ACC_OV_OF_MODE,
+				  ACC_OV_REG_MODE_MASK_MSI_ENABLE);
+		pci_disable_msi(pdev);
+		card->msi_enabled = false;
+	}
+}
+
+static int pci402_init_dma(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	int err;
+
+	err = pci_set_consistent_dma_mask(pdev, PCI402_DMA_MASK);
+	if (err) {
+		pci_err(pdev, "DMA set mask failed!\n");
+		return err;
+	}
+
+	card->dma_buf = pci_alloc_consistent(pdev, PCI402_DMA_SIZE,
+					     &card->dma_hnd);
+	if (!card->dma_buf) {
+		pci_err(pdev, "DMA alloc failed!\n");
+		return -ENOMEM;
+	}
+	if ((card->dma_hnd & PCI402_DMA_MASK) != card->dma_hnd) {
+		pci_err(pdev, "Misaligned DMA buffer: address %px, DMA %pad, mask %llx\n",
+			card->dma_buf, &card->dma_hnd, (u64)PCI402_DMA_MASK);
+		pci_free_consistent(pdev, PCI402_DMA_SIZE, card->dma_buf,
+				    card->dma_hnd);
+		card->dma_buf = NULL;
+		return -ENOMEM;
+	}
+
+	acc_init_bm_ptr(&card->ov, card->cores, card->dma_buf);
+
+	iowrite32((u32)card->dma_hnd,
+		  card->addr_pciep + PCI402_PCIEP_OF_BM_ADDR_LO);
+	iowrite32(0, card->addr_pciep + PCI402_PCIEP_OF_BM_ADDR_HI);
+
+	pci_set_master(pdev);
+
+	acc_ov_set_bits(&card->ov, ACC_OV_OF_MODE,
+			ACC_OV_REG_MODE_MASK_BM_ENABLE);
+
+	return 0;
+}
+
+static void pci402_finish_dma(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	int i;
+
+	acc_ov_clear_bits(&card->ov, ACC_OV_OF_MODE,
+			  ACC_OV_REG_MODE_MASK_BM_ENABLE);
+
+	pci_clear_master(pdev);
+
+	iowrite32(0, card->addr_pciep + PCI402_PCIEP_OF_BM_ADDR_LO);
+	iowrite32(0, card->addr_pciep + PCI402_PCIEP_OF_BM_ADDR_HI);
+
+	card->ov.bmfifo.messages = NULL;
+	card->ov.bmfifo.irq_cnt = NULL;
+	for (i = 0; i < card->ov.active_cores; i++) {
+		struct acc_core *core = &card->cores[i];
+
+		core->bmfifo.messages = NULL;
+		core->bmfifo.irq_cnt = NULL;
+	}
+
+	pci_free_consistent(pdev, PCI402_DMA_SIZE, card->dma_buf,
+			    card->dma_hnd);
+	card->dma_buf = NULL;
+}
+
+static int pci402_init_cores(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	int err;
+	int i;
+
+	for (i = 0; i < card->ov.active_cores; i++) {
+		struct acc_core *core = &card->cores[i];
+		struct acc_net_priv *priv;
+		struct net_device *netdev;
+		u32 fifo_config;
+
+		core->addr = card->ov.addr + (i + 1) * PCI402_IO_LEN_CORE;
+
+		fifo_config = acc_read32(core, ACC_CORE_OF_TXFIFO_CONFIG);
+		core->tx_fifo_size = (u8)(fifo_config >> 24);
+		if (core->tx_fifo_size <= 1) {
+			pci_err(pdev, "Invalid tx_fifo_size!\n");
+			err = -EINVAL;
+			goto failure;
+		}
+
+		netdev = alloc_candev(sizeof(*priv), core->tx_fifo_size);
+		if (!netdev) {
+			err = -ENOMEM;
+			goto failure;
+		}
+		core->net_dev = netdev;
+
+		netdev->flags |= IFF_ECHO;
+		netdev->netdev_ops = &pci402_acc_netdev_ops;
+		SET_NETDEV_DEV(netdev, &pdev->dev);
+
+		priv = netdev_priv(netdev);
+		priv->can.state = CAN_STATE_STOPPED;
+		priv->can.ctrlmode_supported = CAN_CTRLMODE_LISTENONLY |
+			CAN_CTRLMODE_BERR_REPORTING |
+			CAN_CTRLMODE_CC_LEN8_DLC |
+			CAN_CTRLMODE_LOOPBACK;
+		priv->can.clock.freq = card->ov.core_frequency;
+		priv->can.bittiming_const =
+			(card->ov.features & ACC_OV_REG_FEAT_MASK_CANFD) ?
+			&pci402_bittiming_const_canfd :
+			&pci402_bittiming_const;
+		priv->can.do_set_bittiming = acc_set_bittiming;
+		priv->can.do_set_mode = acc_set_mode;
+		priv->can.do_get_berr_counter = acc_get_berr_counter;
+
+		priv->core = core;
+		priv->ov = &card->ov;
+
+		err = register_candev(netdev);
+		if (err) {
+			free_candev(core->net_dev);
+			core->net_dev = NULL;
+			goto failure;
+		}
+
+		netdev_info(netdev, "registered\n");
+	}
+
+	return 0;
+
+failure:
+	for (i--; i >= 0; i--) {
+		struct acc_core *core = &card->cores[i];
+
+		netdev_info(core->net_dev, "unregistering...\n");
+		unregister_candev(core->net_dev);
+
+		free_candev(core->net_dev);
+		core->net_dev = NULL;
+	}
+
+	return err;
+}
+
+static void pci402_finish_cores(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < card->ov.active_cores; i++) {
+		struct acc_core *core = &card->cores[i];
+
+		netdev_info(core->net_dev, "unregister\n");
+		unregister_candev(core->net_dev);
+
+		free_candev(core->net_dev);
+		core->net_dev = NULL;
+	}
+}
+
+static int pci402_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	struct pci402_card *card = NULL;
+	int err;
+
+	err = pci_enable_device(pdev);
+	if (err)
+		return err;
+
+	card = devm_kzalloc(&pdev->dev, sizeof(*card), GFP_KERNEL);
+	if (!card)
+		goto failure_disable_pci;
+
+	pci_set_drvdata(pdev, card);
+
+	err = pci_request_regions(pdev, pci_name(pdev));
+	if (err)
+		goto failure_free_card;
+
+	card->addr = pci_iomap(pdev, PCI402_BAR, PCI402_IO_LEN_TOTAL);
+	if (!card->addr) {
+		err = -ENOMEM;
+		goto failure_release_regions;
+	}
+
+	err = pci402_init_card(pdev);
+	if (err)
+		goto failure_unmap;
+
+	err = pci402_init_dma(pdev);
+	if (err)
+		goto failure_unmap;
+
+	err = pci402_init_interrupt(pdev);
+	if (err)
+		goto failure_finish_dma;
+
+	err = pci402_init_cores(pdev);
+	if (err)
+		goto failure_finish_interrupt;
+
+	return 0;
+
+failure_finish_interrupt:
+	pci402_finish_interrupt(pdev);
+
+failure_finish_dma:
+	pci402_finish_dma(pdev);
+
+failure_unmap:
+	pci_iounmap(pdev, card->addr);
+
+failure_release_regions:
+	pci_release_regions(pdev);
+
+failure_free_card:
+	devm_kfree(&pdev->dev, card);
+
+failure_disable_pci:
+	pci_disable_device(pdev);
+
+	return err;
+}
+
+static void pci402_remove(struct pci_dev *pdev)
+{
+	struct pci402_card *card = pci_get_drvdata(pdev);
+
+	pci402_finish_interrupt(pdev);
+	pci402_finish_cores(pdev);
+	pci402_finish_dma(pdev);
+	pci_iounmap(pdev, card->addr);
+	pci_release_regions(pdev);
+	pci_disable_device(pdev);
+	devm_kfree(&pdev->dev, card);
+}
+
+static const struct pci_device_id pci402_tbl[] = {
+	{ PCI_VENDOR_ID_ESDGMBH, ESD_PCI_DEVICE_ID_PCIE402,
+			PCI_ANY_ID, PCI_ANY_ID, },
+	{ 0, }
+};
+MODULE_DEVICE_TABLE(pci, pci402_tbl);
+
+static struct pci_driver pci402_driver = {
+	.name = DRV_NAME,
+	.id_table = pci402_tbl,
+	.probe = pci402_probe,
+	.remove = pci402_remove,
+};
+
+module_pci_driver(pci402_driver);
+
+MODULE_DESCRIPTION("Socket-CAN driver for esd CAN PCI(e)/402 cards");
+MODULE_AUTHOR("Thomas Körper <thomas.koerper@esd.eu>");
+MODULE_AUTHOR("Stefan Mätje <stefan.maetje@esd.eu>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/net/can/esd/esdacc.c b/drivers/net/can/esd/esdacc.c
new file mode 100644
index 000000000000..bc85b948db6c
--- /dev/null
+++ b/drivers/net/can/esd/esdacc.c
@@ -0,0 +1,717 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (C) 2015 - 2017 esd electronic system design gmbh
+ * Copyright (C) 2017 - 2021 esd electronics gmbh
+ */
+
+#include <linux/ktime.h>
+#include <linux/gcd.h>
+#include <linux/io.h>
+#include <linux/delay.h>
+#include "esdacc.h"
+
+/* ecc value of esdACC equals SJA1000's ECC register */
+#define ACC_ECC_SEG			0x1f
+#define ACC_ECC_DIR			0x20
+#define ACC_ECC_BIT			0x00
+#define ACC_ECC_FORM			0x40
+#define ACC_ECC_STUFF			0x80
+#define ACC_ECC_MASK			0xc0
+
+#define ACC_BM_IRQ_UNMASK_ALL		0x55555555U
+#define ACC_BM_IRQ_MASK_ALL		0xaaaaaaaaU
+#define ACC_BM_IRQ_MASK			0x2U
+#define ACC_BM_IRQ_UNMASK		0x1U
+#define ACC_BM_LENFLAG_TX		0x20
+
+#define ACC_REG_STATUS_IDX_STATUS_DOS	16
+#define ACC_REG_STATUS_IDX_STATUS_ES	17
+#define ACC_REG_STATUS_IDX_STATUS_EP	18
+#define ACC_REG_STATUS_IDX_STATUS_BS	19
+#define ACC_REG_STATUS_IDX_STATUS_RBS	20
+#define ACC_REG_STATUS_IDX_STATUS_RS	21
+#define ACC_REG_STATUS_MASK_STATUS_DOS	BIT(ACC_REG_STATUS_IDX_STATUS_DOS)
+#define ACC_REG_STATUS_MASK_STATUS_ES	BIT(ACC_REG_STATUS_IDX_STATUS_ES)
+#define ACC_REG_STATUS_MASK_STATUS_EP	BIT(ACC_REG_STATUS_IDX_STATUS_EP)
+#define ACC_REG_STATUS_MASK_STATUS_BS	BIT(ACC_REG_STATUS_IDX_STATUS_BS)
+#define ACC_REG_STATUS_MASK_STATUS_RBS	BIT(ACC_REG_STATUS_IDX_STATUS_RBS)
+#define ACC_REG_STATUS_MASK_STATUS_RS	BIT(ACC_REG_STATUS_IDX_STATUS_RS)
+
+static void acc_resetmode_enter(struct acc_core *core)
+{
+	int i;
+
+	acc_set_bits(core, ACC_CORE_OF_CTRL_MODE,
+		     ACC_REG_CONTROL_MASK_MODE_RESETMODE);
+
+	for (i = 0; i < 10; i++) {
+		if (acc_resetmode_entered(core))
+			return;
+
+		udelay(5);
+	}
+
+	netdev_warn(core->net_dev, "Entering reset mode timed out\n");
+}
+
+static void acc_resetmode_leave(struct acc_core *core)
+{
+	int i;
+
+	acc_clear_bits(core, ACC_CORE_OF_CTRL_MODE,
+		       ACC_REG_CONTROL_MASK_MODE_RESETMODE);
+
+	for (i = 0; i < 10; i++) {
+		if (!acc_resetmode_entered(core))
+			return;
+
+		udelay(5);
+	}
+
+	netdev_warn(core->net_dev, "Leaving reset mode timed out\n");
+}
+
+static void acc_txq_put(struct acc_core *core, u32 acc_id, u8 acc_dlc,
+			const void *data)
+{
+	acc_write32_noswap(core, ACC_CORE_OF_TXFIFO_DATA_1,
+			   *((const u32 *)(data + 4)));
+	acc_write32_noswap(core, ACC_CORE_OF_TXFIFO_DATA_0,
+			   *((const u32 *)data));
+	acc_write32(core, ACC_CORE_OF_TXFIFO_DLC, acc_dlc);
+	/* CAN id must be written at last. This write starts TX. */
+	acc_write32(core, ACC_CORE_OF_TXFIFO_ID, acc_id);
+}
+
+/* Prepare conversion factor from ESDACC time stamp ticks to ns
+ *
+ * The conversion factor ts2ns from time stamp counts to ns is basically
+ *	ts2ns = NSEC_PER_SEC / timestamp_frequency
+ *
+ * To avoid an overflow, the ts2ns fraction is truncated with its gcd and
+ * only the truncated numerator and denominator are used further.
+ */
+static void acc_init_ov_ts2ns(struct acc_ov *ov)
+{
+	u32 ts2ns_gcd = (u32)gcd(NSEC_PER_SEC, ov->timestamp_frequency);
+
+	ov->ts2ns_numerator = (u32)NSEC_PER_SEC / ts2ns_gcd;
+	ov->ts2ns_denominator = ov->timestamp_frequency / ts2ns_gcd;
+}
+
+static ktime_t acc_ts2ktime(struct acc_ov *ov, u64 ts)
+{
+	u64 ns;
+
+	ts = ts * ov->ts2ns_numerator;
+	ns = div_u64(ts, ov->ts2ns_denominator);
+
+	return ns_to_ktime(ns);
+}
+
+void acc_init_ov(struct acc_ov *ov, struct device *dev)
+{
+	u32 temp;
+	/* For the justification of this see comment on struct acc_bmmsg*
+	 * in esdacc.h.
+	 */
+	BUILD_BUG_ON(sizeof(struct acc_bmmsg) != ACC_CORE_DMAMSG_SIZE);
+
+	temp = acc_ov_read32(ov, ACC_OV_OF_VERSION);
+	ov->version = (u16)temp;
+	ov->features = (u16)(temp >> 16);
+
+	temp = acc_ov_read32(ov, ACC_OV_OF_INFO);
+	ov->total_cores = (u8)temp;
+	ov->active_cores = (u8)(temp >> 8);
+
+	ov->core_frequency = acc_ov_read32(ov, ACC_OV_OF_CANCORE_FREQ);
+	ov->timestamp_frequency = acc_ov_read32(ov, ACC_OV_OF_TS_FREQ_LO);
+	acc_init_ov_ts2ns(ov);
+
+	/* Depending on ESDACC feature NEW_PSC enable the new prescaler
+	 * or adjust core_frequency according to the implicit division by 2.
+	 */
+	if (ov->features & ACC_OV_REG_FEAT_MASK_NEW_PSC) {
+		acc_ov_set_bits(ov, ACC_OV_OF_MODE,
+				ACC_OV_REG_MODE_MASK_NEW_PSC_ENABLE);
+	} else {
+		ov->core_frequency /= 2;
+	}
+
+	dev_info(dev,
+		 "ESDACC v%u, freq: %u/%u, feat/strap: 0x%x/0x%x, cores: %u/%u\n",
+		 ov->version, ov->core_frequency, ov->timestamp_frequency,
+		 ov->features, acc_ov_read32(ov, ACC_OV_OF_INFO) >> 16,
+		 ov->active_cores, ov->total_cores);
+	dev_dbg(dev, "ESDACC ts2ns: numerator %u, denominator %u\n",
+		ov->ts2ns_numerator, ov->ts2ns_denominator);
+}
+
+void acc_init_bm_ptr(struct acc_ov *ov, struct acc_core *cores, const void *mem)
+{
+	unsigned int u;
+
+	/* DMA buffer layout as follows where N is the number of CAN cores
+	 * implemented in the FPGA, i.e. N = ov->total_cores
+	 *
+	 *   Layout                   Section size
+	 * +-----------------------+
+	 * | FIFO Card/Overview	   |  ACC_CORE_DMABUF_SIZE
+	 * |			   |
+	 * +-----------------------+
+	 * | FIFO Core0		   |  ACC_CORE_DMABUF_SIZE
+	 * |			   |
+	 * +-----------------------+
+	 * | ...		   |  ...
+	 * |			   |
+	 * +-----------------------+
+	 * | FIFO CoreN		   |  ACC_CORE_DMABUF_SIZE
+	 * |			   |
+	 * +-----------------------+
+	 * | irq_cnt Card/Overview |  sizeof(u32)
+	 * +-----------------------+
+	 * | irq_cnt Core0	   |  sizeof(u32)
+	 * +-----------------------+
+	 * | ...		   |  ...
+	 * +-----------------------+
+	 * | irq_cnt CoreN	   |  sizeof(u32)
+	 * +-----------------------+
+	 */
+	ov->bmfifo.messages = mem;
+	ov->bmfifo.irq_cnt = mem + (ov->total_cores + 1U) * ACC_CORE_DMABUF_SIZE;
+
+	for (u = 0U; u < ov->active_cores; u++) {
+		struct acc_core *core = &cores[u];
+
+		core->bmfifo.messages = mem + (u + 1U) * ACC_CORE_DMABUF_SIZE;
+		core->bmfifo.irq_cnt = ov->bmfifo.irq_cnt + (u + 1U);
+	}
+}
+
+int acc_open(struct net_device *netdev)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+	u32 ctrl_mode;
+	int err;
+
+	err = open_candev(netdev);
+	if (err)
+		return err;
+
+	ctrl_mode = ACC_REG_CONTROL_MASK_IE_RXTX |
+			ACC_REG_CONTROL_MASK_IE_TXERROR |
+			ACC_REG_CONTROL_MASK_IE_ERRWARN |
+			ACC_REG_CONTROL_MASK_IE_OVERRUN |
+			ACC_REG_CONTROL_MASK_IE_ERRPASS;
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_BERR_REPORTING)
+		ctrl_mode |= ACC_REG_CONTROL_MASK_IE_BUSERR;
+
+	acc_set_bits(priv->core, ACC_CORE_OF_CTRL_MODE, ctrl_mode);
+
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+	netif_start_queue(netdev);
+	return 0;
+}
+
+int acc_close(struct net_device *netdev)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+
+	acc_clear_bits(priv->core, ACC_CORE_OF_CTRL_MODE,
+		       ACC_REG_CONTROL_MASK_IE_RXTX |
+		       ACC_REG_CONTROL_MASK_IE_TXERROR |
+		       ACC_REG_CONTROL_MASK_IE_ERRWARN |
+		       ACC_REG_CONTROL_MASK_IE_OVERRUN |
+		       ACC_REG_CONTROL_MASK_IE_ERRPASS |
+		       ACC_REG_CONTROL_MASK_IE_BUSERR);
+
+	netif_stop_queue(netdev);
+	priv->can.state = CAN_STATE_STOPPED;
+
+	close_candev(netdev);
+	return 0;
+}
+
+netdev_tx_t acc_start_xmit(struct sk_buff *skb, struct net_device *netdev)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+	struct acc_core *core = priv->core;
+	struct can_frame *cf = (struct can_frame *)skb->data;
+	u8 tx_fifo_head = core->tx_fifo_head;
+	int fifo_usage;
+	u32 acc_id;
+	u8 acc_dlc;
+
+	/* Access core->tx_fifo_tail only once because it may be changed
+	 * from the interrupt level.
+	 */
+	fifo_usage = tx_fifo_head - core->tx_fifo_tail;
+	if (fifo_usage < 0)
+		fifo_usage += core->tx_fifo_size;
+
+	if (fifo_usage >= core->tx_fifo_size - 1) {
+		netdev_err(core->net_dev,
+			   "BUG: TX ring full when queue awake!\n");
+		netif_stop_queue(netdev);
+		return NETDEV_TX_BUSY;
+	}
+
+	if (fifo_usage == core->tx_fifo_size - 2)
+		netif_stop_queue(netdev);
+
+	acc_dlc = can_get_cc_dlc(cf, priv->can.ctrlmode);
+	if (cf->can_id & CAN_RTR_FLAG)
+		acc_dlc |= ACC_CAN_RTR_FLAG;
+
+	if (cf->can_id & CAN_EFF_FLAG) {
+		acc_id = cf->can_id & CAN_EFF_MASK;
+		acc_id |= ACC_CAN_EFF_FLAG;
+	} else {
+		acc_id = cf->can_id & CAN_SFF_MASK;
+	}
+
+	can_put_echo_skb(skb, netdev, core->tx_fifo_head, 0);
+
+	++tx_fifo_head;
+	if (tx_fifo_head >= core->tx_fifo_size)
+		tx_fifo_head = 0U;
+	core->tx_fifo_head = tx_fifo_head;
+
+	acc_txq_put(core, acc_id, acc_dlc, cf->data);
+
+	return NETDEV_TX_OK;
+}
+
+int acc_get_berr_counter(const struct net_device *netdev,
+			 struct can_berr_counter *bec)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+	u32 core_status = acc_read32(priv->core, ACC_CORE_OF_STATUS);
+
+	bec->txerr = (core_status >> 8) & 0xff;
+	bec->rxerr = core_status & 0xff;
+
+	return 0;
+}
+
+int acc_set_mode(struct net_device *netdev, enum can_mode mode)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+
+	switch (mode) {
+	case CAN_MODE_START:
+		acc_resetmode_leave(priv->core);
+		netif_wake_queue(netdev);
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}
+
+	return 0;
+}
+
+int acc_set_bittiming(struct net_device *netdev)
+{
+	struct acc_net_priv *priv = netdev_priv(netdev);
+	const struct can_bittiming *bt = &priv->can.bittiming;
+#if ACC_ENABLE_CANFD
+	const struct can_bittiming *dbt = &priv->can.data_bittiming;
+#endif
+	u32 brp = bt->brp - 1;
+	u32 btr;
+
+	acc_resetmode_enter(priv->core);
+
+	if (priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY)
+		acc_set_bits(priv->core, ACC_CORE_OF_CTRL_MODE,
+			     ACC_REG_CONTROL_MASK_MODE_LOM);
+	else
+		acc_clear_bits(priv->core, ACC_CORE_OF_CTRL_MODE,
+			       ACC_REG_CONTROL_MASK_MODE_LOM);
+
+	if (priv->ov->features & ACC_OV_REG_FEAT_MASK_CANFD) {
+		u32 fbtr = 0;
+
+		netdev_dbg(priv->core->net_dev,
+			   "bit timing: brp %u, prop %u, ph1 %u ph2 %u, sjw %u\n",
+			   bt->brp, bt->prop_seg,
+			   bt->phase_seg1, bt->phase_seg2, bt->sjw);
+
+		/* BRP: 8 bits @ bits 7..0 */
+		brp &= 0xff;
+
+		/* TSEG1: 8 bits @ bits 7..0 */
+		btr = (bt->phase_seg1 + bt->prop_seg - 1) & 0xff;
+		/* TSEG2: 7 bits @ bits 22..16 */
+		btr |= ((bt->phase_seg2 - 1) & 0x7f) << 16;
+		/* SJW: 7 bits @ bits 30..24 */
+		btr |= ((bt->sjw - 1) & 0x7f) << 24;
+
+		/* Keep order of accesses to ACC_CORE_OF_BRP and ACC_CORE_OF_BTR. */
+		acc_write32(priv->core, ACC_CORE_OF_BRP, brp);
+		acc_write32(priv->core, ACC_CORE_OF_BTR, btr);
+
+#if ACC_ENABLE_CANFD
+		/* Add setup of ACC_CORE_OF_FBTR for CAN-FD data phase here. */
+		acc_write32(priv->core, ACC_CORE_OF_FBTR, fbtr);
+#endif
+
+		netdev_info(priv->core->net_dev,
+			    "ESDACC: BRP %u, NBTR 0x%08x, DBTR 0x%08x",
+			    brp, btr, fbtr);
+	} else {
+		netdev_dbg(priv->core->net_dev,
+			   "bit timing: brp %u, prop %u, ph1 %u ph2 %u, sjw %u\n",
+			   bt->brp, bt->prop_seg,
+			   bt->phase_seg1, bt->phase_seg2, bt->sjw);
+
+		/* BRP: 9 bits @ bits 8..0 */
+		brp &= 0x1ff;
+
+		/* TSEG1: 4 bits @ bits 3..0 */
+		btr = (bt->phase_seg1 + bt->prop_seg - 1) & 0xf;
+		/* TSEG2: 3 bits @ bits 18..16*/
+		btr |= ((bt->phase_seg2 - 1) & 0x7) << 16;
+		/* SJW: 2 bits @ bits 25..24 */
+		btr |= ((bt->sjw - 1) & 0x3) << 24;
+
+		/* Keep order of accesses to ACC_CORE_OF_BRP and ACC_CORE_OF_BTR. */
+		acc_write32(priv->core, ACC_CORE_OF_BRP, brp);
+		acc_write32(priv->core, ACC_CORE_OF_BTR, btr);
+
+		netdev_info(priv->core->net_dev, "ESDACC: BRP %u, BTR 0x%08x",
+			    brp, btr);
+	}
+
+	acc_resetmode_leave(priv->core);
+	priv->can.state = CAN_STATE_ERROR_ACTIVE;
+
+	return 0;
+}
+
+static void handle_core_msg_rxtxdone(struct acc_core *core,
+				     const struct acc_bmmsg_rxtxdone *msg)
+{
+	struct acc_net_priv *priv = netdev_priv(core->net_dev);
+	struct net_device_stats *stats = &core->net_dev->stats;
+	struct sk_buff *skb;
+
+	if (msg->dlc.rxtx.len & ACC_BM_LENFLAG_TX) {
+		u8 tx_fifo_tail = core->tx_fifo_tail;
+
+		if (core->tx_fifo_head == tx_fifo_tail) {
+			netdev_warn(core->net_dev,
+				    "TX interrupt, but queue is empty!?\n");
+			return;
+		}
+
+		/* Direct access echo skb to attach HW time stamp. */
+		skb = priv->can.echo_skb[tx_fifo_tail];
+		if (skb) {
+			skb_hwtstamps(skb)->hwtstamp =
+				acc_ts2ktime(priv->ov, msg->ts);
+		}
+
+		stats->tx_packets++;
+		stats->tx_bytes += can_get_echo_skb(core->net_dev, tx_fifo_tail,
+						    NULL);
+
+		++tx_fifo_tail;
+		if (tx_fifo_tail >= core->tx_fifo_size)
+			tx_fifo_tail = 0U;
+		core->tx_fifo_tail = tx_fifo_tail;
+
+		netif_wake_queue(core->net_dev);
+
+	} else {
+		struct can_frame *cf;
+
+		skb = alloc_can_skb(core->net_dev, &cf);
+		if (!skb) {
+			stats->rx_dropped++;
+			return;
+		}
+
+		cf->can_id = msg->id & CAN_EFF_MASK;
+		if (msg->id & ACC_CAN_EFF_FLAG)
+			cf->can_id |= CAN_EFF_FLAG;
+
+		can_frame_set_cc_len(cf, msg->dlc.rx.len & ACC_CAN_DLC_MASK,
+				     priv->can.ctrlmode);
+
+		if (msg->dlc.rx.len & ACC_CAN_RTR_FLAG)
+			cf->can_id |= CAN_RTR_FLAG;
+		else
+			memcpy(cf->data, msg->data, cf->len);
+
+		skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
+
+		stats->rx_packets++;
+		stats->rx_bytes += cf->len;
+		netif_rx(skb);
+	}
+}
+
+static void handle_core_msg_txabort(struct acc_core *core,
+				    const struct acc_bmmsg_txabort *msg)
+{
+	struct net_device_stats *stats = &core->net_dev->stats;
+	unsigned int u;
+
+	/* abort_mask signals which frames were aborted in card's fifo */
+	for (u = 0U; u < sizeof(msg->abort_mask) * BITS_PER_BYTE; u++) {
+		if (!(msg->abort_mask & (1U << u)))
+			continue;
+
+		if (core->tx_fifo_head == core->tx_fifo_tail) {
+			netdev_warn(core->net_dev,
+				    "TX Err interrupt, but queue is empty!?\n");
+			break;
+		}
+		stats->tx_errors++;
+
+		can_free_echo_skb(core->net_dev, core->tx_fifo_tail, NULL);
+		core->tx_fifo_tail++;
+		if (core->tx_fifo_tail >= core->tx_fifo_size)
+			core->tx_fifo_tail = 0;
+	}
+
+	if (!acc_resetmode_entered(core))
+		netif_wake_queue(core->net_dev);
+}
+
+static void handle_core_msg_overrun(struct acc_core *core,
+				    const struct acc_bmmsg_overrun *msg)
+{
+	struct acc_net_priv *priv = netdev_priv(core->net_dev);
+	struct net_device_stats *stats = &core->net_dev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	skb = alloc_can_err_skb(core->net_dev, &cf);
+	if (!skb)
+		return;
+
+	/* lost_cnt may be 0 if not supported by ESDACC version */
+	if (msg->lost_cnt) {
+		stats->rx_dropped += msg->lost_cnt;
+		stats->rx_over_errors += msg->lost_cnt;
+	} else {
+		stats->rx_dropped++;
+		stats->rx_over_errors++;
+	}
+
+	cf->can_id |= CAN_ERR_CRTL;
+	cf->data[1] = CAN_ERR_CRTL_RX_OVERFLOW;
+
+	skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->len;
+	netif_rx(skb);
+}
+
+static void handle_core_msg_buserr(struct acc_core *core,
+				   const struct acc_bmmsg_buserr *msg)
+{
+	struct acc_net_priv *priv = netdev_priv(core->net_dev);
+	struct net_device_stats *stats = &core->net_dev->stats;
+	struct can_frame *cf;
+	struct sk_buff *skb;
+
+	priv->can.can_stats.bus_error++;
+
+	skb = alloc_can_err_skb(core->net_dev, &cf);
+	if (!skb)
+		return;
+
+	cf->can_id |= CAN_ERR_PROT | CAN_ERR_BUSERROR;
+
+	/* msg->ecc acts like SJA1000's ECC register */
+	switch (msg->ecc & ACC_ECC_MASK) {
+	case ACC_ECC_BIT:
+		cf->data[2] |= CAN_ERR_PROT_BIT;
+		break;
+	case ACC_ECC_FORM:
+		cf->data[2] |= CAN_ERR_PROT_FORM;
+		break;
+	case ACC_ECC_STUFF:
+		cf->data[2] |= CAN_ERR_PROT_STUFF;
+		break;
+	default:
+		cf->data[2] |= CAN_ERR_PROT_UNSPEC;
+		break;
+	}
+
+	/* Set error location */
+	cf->data[3] = msg->ecc & ACC_ECC_SEG;
+
+	/* Error occurred during transmission? */
+	if ((msg->ecc & ACC_ECC_DIR) == 0) {
+		cf->data[2] |= CAN_ERR_PROT_TX;
+		stats->tx_errors++;
+	} else {
+		stats->rx_errors++;
+	}
+
+	skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
+
+	stats->rx_packets++;
+	stats->rx_bytes += cf->len;
+	netif_rx(skb);
+}
+
+static void
+handle_core_msg_errstatechange(struct acc_core *core,
+			       const struct acc_bmmsg_errstatechange *msg)
+{
+	struct acc_net_priv *priv = netdev_priv(core->net_dev);
+	struct net_device_stats *stats = &core->net_dev->stats;
+	struct can_frame *cf = NULL;
+	struct sk_buff *skb;
+	const u32 reg_status = msg->reg_status;
+	const u8 txerr = (u8)(reg_status >> 8);
+	const u8 rxerr = (u8)reg_status;
+	enum can_state new_state;
+
+	if (reg_status & ACC_REG_STATUS_MASK_STATUS_BS)
+		new_state = CAN_STATE_BUS_OFF;
+	else if (reg_status & ACC_REG_STATUS_MASK_STATUS_EP)
+		new_state = CAN_STATE_ERROR_PASSIVE;
+	else if (reg_status & ACC_REG_STATUS_MASK_STATUS_ES)
+		new_state = CAN_STATE_ERROR_WARNING;
+	else
+		new_state = CAN_STATE_ERROR_ACTIVE;
+
+	skb = alloc_can_err_skb(core->net_dev, &cf);
+
+	if (new_state != priv->can.state) {
+		enum can_state tx_state, rx_state;
+
+		tx_state = (txerr >= rxerr) ?
+			new_state : CAN_STATE_ERROR_ACTIVE;
+		rx_state = (rxerr >= txerr) ?
+			new_state : CAN_STATE_ERROR_ACTIVE;
+
+		/* Always call can_change_state() to update the state
+		 * even if alloc_can_err_skb() may have failed.
+		 * can_change_state() can cope with a NULL cf pointer.
+		 */
+		can_change_state(core->net_dev, cf, tx_state, rx_state);
+	}
+
+	if (skb) {
+		cf->data[6] = txerr;
+		cf->data[7] = rxerr;
+
+		skb_hwtstamps(skb)->hwtstamp = acc_ts2ktime(priv->ov, msg->ts);
+
+		stats->rx_packets++;
+		stats->rx_bytes += cf->len;
+		netif_rx(skb);
+	} else {
+		stats->rx_dropped++;
+	}
+
+	if (new_state == CAN_STATE_BUS_OFF) {
+		acc_write32(core, ACC_CORE_OF_TX_ABORT_MASK, 0xffff);
+		can_bus_off(core->net_dev);
+	}
+}
+
+static void handle_core_interrupt(struct acc_core *core)
+{
+	u32 msg_fifo_head = core->bmfifo.local_irq_cnt & 0xff;
+
+	while (core->bmfifo.msg_fifo_tail != msg_fifo_head) {
+		const struct acc_bmmsg *msg =
+			&core->bmfifo.messages[core->bmfifo.msg_fifo_tail];
+
+		switch (msg->u.msg_id) {
+		case BM_MSG_ID_RXTXDONE:
+			handle_core_msg_rxtxdone(core, &msg->u.rxtxdone);
+			break;
+
+		case BM_MSG_ID_TXABORT:
+			handle_core_msg_txabort(core, &msg->u.txabort);
+			break;
+
+		case BM_MSG_ID_OVERRUN:
+			handle_core_msg_overrun(core, &msg->u.overrun);
+			break;
+
+		case BM_MSG_ID_BUSERR:
+			handle_core_msg_buserr(core, &msg->u.buserr);
+			break;
+
+		case BM_MSG_ID_ERRPASSIVE:
+		case BM_MSG_ID_ERRWARN:
+			handle_core_msg_errstatechange(core,
+						       &msg->u.errstatechange);
+			break;
+
+		default:
+			/* Ignore all other BM messages (like the CAN-FD messages) */
+			break;
+		}
+
+		core->bmfifo.msg_fifo_tail =
+				(core->bmfifo.msg_fifo_tail + 1) & 0xff;
+	}
+}
+
+irqreturn_t acc_card_interrupt(struct acc_ov *ov, struct acc_core *cores)
+{
+	u32		irqmask;
+	int		i;
+
+	/* First we look for whom interrupts are pending, card/overview
+	 * or any of the cores. Two bits in irqmask are used for each;
+	 * set to ACC_BM_IRQ_MASK then:
+	 */
+	irqmask = 0;
+	if (*ov->bmfifo.irq_cnt != ov->bmfifo.local_irq_cnt) {
+		irqmask |= ACC_BM_IRQ_MASK;
+		ov->bmfifo.local_irq_cnt = *ov->bmfifo.irq_cnt;
+	}
+
+	for (i = 0; i < ov->active_cores; i++) {
+		struct acc_core *core = &cores[i];
+
+		if (*core->bmfifo.irq_cnt != core->bmfifo.local_irq_cnt) {
+			irqmask |= (ACC_BM_IRQ_MASK << (2 * (i + 1)));
+			core->bmfifo.local_irq_cnt = *core->bmfifo.irq_cnt;
+		}
+	}
+
+	if (!irqmask)
+		return IRQ_NONE;
+
+	/* At second we tell the card we're working on them by writing irqmask,
+	 * call handle_{ov|core}_interrupt and then acknowledge the
+	 * interrupts by writing irq_cnt:
+	 */
+	acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_MASK, irqmask);
+
+	if (irqmask & ACC_BM_IRQ_MASK) {
+		/* handle_ov_interrupt(); - no use yet. */
+		acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_COUNTER,
+			       ov->bmfifo.local_irq_cnt);
+	}
+
+	for (i = 0; i < ov->active_cores; i++) {
+		struct acc_core *core = &cores[i];
+
+		if (irqmask & (ACC_BM_IRQ_MASK << (2 * (i + 1)))) {
+			handle_core_interrupt(core);
+			acc_write32(core, ACC_OV_OF_BM_IRQ_COUNTER,
+				    core->bmfifo.local_irq_cnt);
+		}
+	}
+
+	acc_ov_write32(ov, ACC_OV_OF_BM_IRQ_MASK, ACC_BM_IRQ_UNMASK_ALL);
+
+	return IRQ_HANDLED;
+}
diff --git a/drivers/net/can/esd/esdacc.h b/drivers/net/can/esd/esdacc.h
new file mode 100644
index 000000000000..f594514c26fb
--- /dev/null
+++ b/drivers/net/can/esd/esdacc.h
@@ -0,0 +1,394 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/* Copyright (C) 2015 - 2017 esd electronic system design gmbh
+ * Copyright (C) 2017 - 2021 esd electronics gmbh
+ */
+
+#include <linux/kernel.h>
+#include <linux/netdevice.h>
+#include <linux/can/dev.h>
+
+#define ACC_ENABLE_CANFD			0
+
+#define ACC_CAN_EFF_FLAG			0x20000000
+#define ACC_CAN_RTR_FLAG			0x10
+#define ACC_CAN_DLC_MASK			0x0f
+
+#define ACC_OV_OF_PROBE				0x0000
+#define ACC_OV_OF_VERSION			0x0004
+#define ACC_OV_OF_INFO				0x0008
+#define ACC_OV_OF_CANCORE_FREQ			0x000c
+#define ACC_OV_OF_TS_FREQ_LO			0x0010
+#define ACC_OV_OF_TS_FREQ_HI			0x0014
+#define ACC_OV_OF_IRQ_STATUS_CORES		0x0018
+#define ACC_OV_OF_TS_CURR_LO			0x001c
+#define ACC_OV_OF_TS_CURR_HI			0x0020
+#define ACC_OV_OF_IRQ_STATUS			0x0028
+#define ACC_OV_OF_MODE				0x002c
+#define ACC_OV_OF_BM_IRQ_COUNTER		0x0070
+#define ACC_OV_OF_BM_IRQ_MASK			0x0074
+#define ACC_OV_OF_MSI_DATA			0x0080
+#define ACC_OV_OF_MSI_ADDRESSOFFSET		0x0084
+
+/* Feature flags are contained in the upper 16 bit of the version
+ * register at ACC_OV_OF_VERSION but only used with these masks after
+ * extraction into an extra variable => (xx - 16).
+ */
+#define ACC_OV_REG_FEAT_IDX_CANFD		(27 - 16)
+#define ACC_OV_REG_FEAT_IDX_NEW_PSC		(28 - 16)
+#define ACC_OV_REG_FEAT_MASK_CANFD		BIT(ACC_OV_REG_FEAT_IDX_CANFD)
+#define ACC_OV_REG_FEAT_MASK_NEW_PSC		BIT(ACC_OV_REG_FEAT_IDX_NEW_PSC)
+
+#define ACC_OV_REG_MODE_MASK_ENDIAN_LITTLE	0x00000001
+#define ACC_OV_REG_MODE_MASK_BM_ENABLE		0x00000002
+#define ACC_OV_REG_MODE_MASK_MODE_LED		0x00000004
+#define ACC_OV_REG_MODE_MASK_TIMER		0x00000070
+#define ACC_OV_REG_MODE_MASK_TIMER_ENABLE	0x00000010
+#define ACC_OV_REG_MODE_MASK_TIMER_ONE_SHOT	0x00000020
+#define ACC_OV_REG_MODE_MASK_TIMER_ABSOLUTE	0x00000040
+#define ACC_OV_REG_MODE_MASK_TS_SRC		0x00000180
+#define ACC_OV_REG_MODE_MASK_I2C_ENABLE		0x00000800
+#define ACC_OV_REG_MODE_MASK_MSI_ENABLE		0x00004000
+#define ACC_OV_REG_MODE_MASK_NEW_PSC_ENABLE	0x00008000
+#define ACC_OV_REG_MODE_MASK_FPGA_RESET		0x80000000
+
+#define ACC_CORE_OF_CTRL_MODE			0x0000
+#define ACC_CORE_OF_STATUS_IRQ			0x0008
+#define ACC_CORE_OF_BRP				0x000c
+#define ACC_CORE_OF_BTR				0x0010
+#define ACC_CORE_OF_FBTR			0x0014
+#define ACC_CORE_OF_STATUS			0x0030
+#define ACC_CORE_OF_TXFIFO_CONFIG		0x0048
+#define ACC_CORE_OF_TXFIFO_STATUS		0x004c
+#define ACC_CORE_OF_TX_STATUS_IRQ		0x0050
+#define ACC_CORE_OF_TX_ABORT_MASK		0x0054
+#define ACC_CORE_OF_BM_IRQ_COUNTER		0x0070
+#define ACC_CORE_OF_TXFIFO_ID			0x00c0
+#define ACC_CORE_OF_TXFIFO_DLC			0x00c4
+#define ACC_CORE_OF_TXFIFO_DATA_0		0x00c8
+#define ACC_CORE_OF_TXFIFO_DATA_1		0x00cc
+
+#define ACC_REG_CONTROL_IDX_MODE_RESETMODE	0
+#define ACC_REG_CONTROL_IDX_MODE_LOM		1
+#define ACC_REG_CONTROL_IDX_MODE_STM		2
+#define ACC_REG_CONTROL_IDX_MODE_TRANSEN	5
+#define ACC_REG_CONTROL_IDX_MODE_TS		6
+#define ACC_REG_CONTROL_IDX_MODE_SCHEDULE	7
+#define ACC_REG_CONTROL_MASK_MODE_RESETMODE	\
+				BIT(ACC_REG_CONTROL_IDX_MODE_RESETMODE)
+#define ACC_REG_CONTROL_MASK_MODE_LOM		\
+				BIT(ACC_REG_CONTROL_IDX_MODE_LOM)
+#define ACC_REG_CONTROL_MASK_MODE_STM		\
+				BIT(ACC_REG_CONTROL_IDX_MODE_STM)
+#define ACC_REG_CONTROL_MASK_MODE_TRANSEN	\
+				BIT(ACC_REG_CONTROL_IDX_MODE_TRANSEN)
+#define ACC_REG_CONTROL_MASK_MODE_TS		\
+				BIT(ACC_REG_CONTROL_IDX_MODE_TS)
+#define ACC_REG_CONTROL_MASK_MODE_SCHEDULE	\
+				BIT(ACC_REG_CONTROL_IDX_MODE_SCHEDULE)
+
+#define ACC_REG_CONTROL_IDX_IE_RXTX	8
+#define ACC_REG_CONTROL_IDX_IE_TXERROR	9
+#define ACC_REG_CONTROL_IDX_IE_ERRWARN	10
+#define ACC_REG_CONTROL_IDX_IE_OVERRUN	11
+#define ACC_REG_CONTROL_IDX_IE_TSI	12
+#define ACC_REG_CONTROL_IDX_IE_ERRPASS	13
+#define ACC_REG_CONTROL_IDX_IE_BUSERR	15
+#define ACC_REG_CONTROL_MASK_IE_RXTX	BIT(ACC_REG_CONTROL_IDX_IE_RXTX)
+#define ACC_REG_CONTROL_MASK_IE_TXERROR BIT(ACC_REG_CONTROL_IDX_IE_TXERROR)
+#define ACC_REG_CONTROL_MASK_IE_ERRWARN BIT(ACC_REG_CONTROL_IDX_IE_ERRWARN)
+#define ACC_REG_CONTROL_MASK_IE_OVERRUN BIT(ACC_REG_CONTROL_IDX_IE_OVERRUN)
+#define ACC_REG_CONTROL_MASK_IE_TSI	BIT(ACC_REG_CONTROL_IDX_IE_TSI)
+#define ACC_REG_CONTROL_MASK_IE_ERRPASS BIT(ACC_REG_CONTROL_IDX_IE_ERRPASS)
+#define ACC_REG_CONTROL_MASK_IE_BUSERR	BIT(ACC_REG_CONTROL_IDX_IE_BUSERR)
+
+/* 256 BM_MSGs of 32 byte size */
+#define ACC_CORE_DMAMSG_SIZE		32U
+#define ACC_CORE_DMABUF_SIZE		(256U * ACC_CORE_DMAMSG_SIZE)
+
+enum acc_bmmsg_id {
+	BM_MSG_ID_RXTXDONE = 0x01,
+	BM_MSG_ID_TXABORT = 0x02,
+	BM_MSG_ID_OVERRUN = 0x03,
+	BM_MSG_ID_BUSERR = 0x04,
+	BM_MSG_ID_ERRPASSIVE = 0x05,
+	BM_MSG_ID_ERRWARN = 0x06,
+	BM_MSG_ID_TIMESLICE = 0x07,
+	BM_MSG_ID_HWTIMER = 0x08,
+	BM_MSG_ID_HOTPLUG = 0x09,
+	BM_MSG_ID_CANFDDATA0 = 0x0a,
+	BM_MSG_ID_CANFDDATA1 = 0x0b
+};
+
+/* The struct acc_bmmsg* structure declarations that follow here provide
+ * access to the ring buffer of bus master messages maintained by the FPGA
+ * bus master engine. All bus master messages have the same size of
+ * ACC_CORE_DMAMSG_SIZE and a minimum alignment of ACC_CORE_DMAMSG_SIZE in
+ * memory.
+ *
+ * All structure members are natural aligned. Therefore we should not need
+ * a __packed attribute. All struct acc_bmmsg* declarations have at least
+ * reserved* members to fill the structure to the full ACC_CORE_DMAMSG_SIZE.
+ *
+ * A failure of this property due padding will be detected at compile time
+ * by BUILD_BUG_ON(sizeof(struct acc_bmmsg) != ACC_CORE_DMAMSG_SIZE)
+ */
+
+struct acc_bmmsg_rxtxdone {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u32 id;
+	union {
+		struct {
+			u8 len;
+			u8 reserved0;
+			u8 bits;
+			u8 state;
+		} rxtx;
+		struct {
+			u8 len;
+			u8 msg_lost;
+			u8 bits;
+			u8 state;
+		} rx;
+		struct {
+			u8 len;
+			u8 txfifo_idx;
+			u8 bits;
+			u8 state;
+		} tx;
+	} dlc;
+	u8 data[8];
+	/* Time stamps in struct acc_ov::timestamp_frequency ticks. */
+	u64 ts;
+};
+
+struct acc_bmmsg_txabort {
+	u8 msg_id;
+	u8 txfifo_level;
+	u16 abort_mask;
+	u8 txtsfifo_level;
+	u8 reserved2[1];
+	u16 abort_mask_txts;
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_overrun {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 lost_cnt;
+	u8 reserved1;
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_buserr {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 ecc;
+	u8 reserved1;
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reg_status;
+	u32 reg_btr;
+	u32 reserved3[2];
+};
+
+struct acc_bmmsg_errstatechange {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reg_status;
+	u32 reserved3[3];
+};
+
+struct acc_bmmsg_timeslice {
+	u8 msg_id;
+	u8 txfifo_level;
+	u8 reserved1[2];
+	u8 txtsfifo_level;
+	u8 reserved2[3];
+	u64 ts;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_hwtimer {
+	u8 msg_id;
+	u8 reserved1[3];
+	u32 reserved2[1];
+	u64 timer;
+	u32 reserved3[4];
+};
+
+struct acc_bmmsg_hotplug {
+	u8 msg_id;
+	u8 reserved1[3];
+	u32 reserved2[7];
+};
+
+struct acc_bmmsg_canfddata {
+	u8 msg_id;
+	u8 reserved1[3];
+	union {
+		u8 ui8[28];
+		u32 ui32[7];
+	} d;
+};
+
+struct acc_bmmsg {
+	union {
+		u8 msg_id;
+		struct acc_bmmsg_rxtxdone rxtxdone;
+		struct acc_bmmsg_canfddata canfddata;
+		struct acc_bmmsg_txabort txabort;
+		struct acc_bmmsg_overrun overrun;
+		struct acc_bmmsg_buserr buserr;
+		struct acc_bmmsg_errstatechange errstatechange;
+		struct acc_bmmsg_timeslice timeslice;
+		struct acc_bmmsg_hwtimer hwtimer;
+	} u;
+};
+
+/* Regarding Documentation/process/volatile-considered-harmful.rst the
+ * forth exception applies to the "irq_cnt" member of the structure
+ * below. The u32 variable "irq_cnt" points to is updated by the ESDACC
+ * FPGA via DMA.
+ */
+struct acc_bmfifo {
+	const struct acc_bmmsg *messages;
+	/* Bits 0..7: bm_fifo head index */
+	volatile const u32 *irq_cnt;
+	u32 local_irq_cnt;
+	u32 msg_fifo_tail;
+};
+
+struct acc_core {
+	void __iomem *addr;
+	struct net_device *net_dev;
+	struct acc_bmfifo bmfifo;
+	u8 tx_fifo_size;
+	u8 tx_fifo_head;
+	u8 tx_fifo_tail;
+};
+
+struct acc_ov {
+	void __iomem *addr;
+	struct acc_bmfifo bmfifo;
+	u32 timestamp_frequency;
+	u32 ts2ns_numerator;
+	u32 ts2ns_denominator;
+	u32 core_frequency;
+	u16 version;
+	u16 features;
+	u8 total_cores;
+	u8 active_cores;
+};
+
+struct acc_net_priv {
+	struct can_priv can; /* must be the first member! */
+	struct acc_core *core;
+	struct acc_ov *ov;
+};
+
+static inline u32 acc_read32(struct acc_core *core, unsigned short offs)
+{
+	return ioread32be(core->addr + offs);
+}
+
+static inline void acc_write32(struct acc_core *core,
+			       unsigned short offs, u32 v)
+{
+	iowrite32be(v, core->addr + offs);
+}
+
+static inline void acc_write32_noswap(struct acc_core *core,
+				      unsigned short offs, u32 v)
+{
+	iowrite32(v, core->addr + offs);
+}
+
+static inline void acc_set_bits(struct acc_core *core,
+				unsigned short offs, u32 mask)
+{
+	u32 v = acc_read32(core, offs);
+
+	v |= mask;
+	acc_write32(core, offs, v);
+}
+
+static inline void acc_clear_bits(struct acc_core *core,
+				  unsigned short offs, u32 mask)
+{
+	u32 v = acc_read32(core, offs);
+
+	v &= ~mask;
+	acc_write32(core, offs, v);
+}
+
+static inline int acc_resetmode_entered(struct acc_core *core)
+{
+	u32 ctrl = acc_read32(core, ACC_CORE_OF_CTRL_MODE);
+
+	return (ctrl & ACC_REG_CONTROL_MASK_MODE_RESETMODE) != 0;
+}
+
+static inline u32 acc_ov_read32(struct acc_ov *ov, unsigned short offs)
+{
+	return ioread32be(ov->addr + offs);
+}
+
+static inline void acc_ov_write32(struct acc_ov *ov,
+				  unsigned short offs, u32 v)
+{
+	iowrite32be(v, ov->addr + offs);
+}
+
+static inline void acc_ov_set_bits(struct acc_ov *ov,
+				   unsigned short offs, u32 b)
+{
+	u32 v = acc_ov_read32(ov, offs);
+
+	v |= b;
+	acc_ov_write32(ov, offs, v);
+}
+
+static inline void acc_ov_clear_bits(struct acc_ov *ov,
+				     unsigned short offs, u32 b)
+{
+	u32 v = acc_ov_read32(ov, offs);
+
+	v &= ~b;
+	acc_ov_write32(ov, offs, v);
+}
+
+static inline void acc_reset_fpga(struct acc_ov *ov)
+{
+	acc_ov_write32(ov, ACC_OV_OF_MODE, ACC_OV_REG_MODE_MASK_FPGA_RESET);
+
+	/* Also reset I^2C, to re-detect card addons at every driver start: */
+	acc_ov_clear_bits(ov, ACC_OV_OF_MODE, ACC_OV_REG_MODE_MASK_I2C_ENABLE);
+	mdelay(2);
+	acc_ov_set_bits(ov, ACC_OV_OF_MODE, ACC_OV_REG_MODE_MASK_I2C_ENABLE);
+	mdelay(10);
+}
+
+void acc_init_ov(struct acc_ov *ov, struct device *dev);
+void acc_init_bm_ptr(struct acc_ov *ov, struct acc_core *cores,
+		     const void *mem);
+int acc_open(struct net_device *netdev);
+int acc_close(struct net_device *netdev);
+netdev_tx_t acc_start_xmit(struct sk_buff *skb, struct net_device *netdev);
+int acc_get_berr_counter(const struct net_device *netdev,
+			 struct can_berr_counter *bec);
+int acc_set_mode(struct net_device *netdev, enum can_mode mode);
+int acc_set_bittiming(struct net_device *netdev);
+irqreturn_t acc_card_interrupt(struct acc_ov *ov, struct acc_core *cores);
-- 
2.25.1


  reply	other threads:[~2021-07-30 17:38 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-30 17:38 [PATCH v2 0/1] " Stefan Mätje
2021-07-30 17:38 ` Stefan Mätje [this message]
2021-08-06 13:31   ` [PATCH v2 1/1] " Marc Kleine-Budde
2021-08-16 22:04     ` Stefan Mätje
2021-08-17  0:14       ` Vincent MAILHOL

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